The following description is provided to assist the understanding of the reader. None of the information provided or references cited is admitted to be prior art to the present technology.
Native lignin is a naturally occurring, cross-linked, amorphous biopolymer that is an integral component of plant biomass. Lignin is the second most abundant biopolymer earth after cellulose, and contributes to the strength and rigidity of plants and trees. Lignin hinders the process of converting wood into paper because most of the lignin must first be removed from wood to liberate wood fibers for the production of paper. Consequently, the pulp and paper industry annually generates over 45 million metric tons of lignin as a by-product of chemically-processed wood pulps and over 10 million metric tons of lignin as a by-product of mechanically-processed wood pulps. Some of the by-product lignin is used to make short-life paper products such as newsprint and telephone directories, but the majority is being used internally by pulp producers as a low-grade fuel for the chemical pulping operation. Accordingly, there is significant economic incentive to find new markets and more valuable uses for by-product lignin.